Service vehicle

ABSTRACT

A hydraulic excavator is equipped with one or more than one downsizing scheme of arranging a bubble removing device for removing bubbles in hydraulic fluid, using a hydraulic tank including a main tank ( 51 ) and a variable capacity tank ( 52 ) arranged separately from each other and/or fitting the variable capacity tank ( 52 ) to the rear surface of the upper cover. Thus, the lateral section of the seat can be ultimately downsized to provide a large space around the seat. Then, unlike the prior art, a canopy or a cab of a large hydraulic excavator can be securely arranged on the upper swing body of a small hydraulic excavator. Since such large parts can be commonly used with large service vehicles, it is possible to significantly reduce the cost of the service vehicle.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a service vehicle typically mountedwith a hydraulically driven work implement such as a hydraulic excavatoror some other construction machine.

[0003] 2. Description of the Related Art

[0004] Relatively small hydraulic excavators having a sluing diametersmaller than of the width of the vehicle on which the hydraulicexcavator is mounted are known to date. In the case of hydraulicexcavators, the upper swing body is mounted on the vehicle main bodyhaving a pair of lower running bodies (generally crawlers). In the caseof such a small hydraulic excavator, the upper swing body turns withinthe width of the vehicle main body including that of the paired lowerrunning bodies so that it does not move out of the width of the vehicle.Therefore, such a hydraulic excavator is advantageously used in citycenters, housing areas and other areas where the lot is normally smallbecause it can make a small turn.

[0005] Canopy type models and cab type models are provided for hydraulicexcavators so that the buyer can choose either a canopy type or a cabtype at the time of purchase. The canopy type model is equipped onlywith a cover type canopy disposed above the operator seat so that it isless costly and the operator can get onto and away from the seat withoutdifficulty. On the other hand, the operator seat of the cab type modelis covered with a box-like cab so that the operator is reliablyprotected against rainfalls and winds and hence he or she cancomfortably work in the cab.

[0006] Meanwhile, dedicated parts are developed and preparedconventionally for small and large hydraulic excavators as a function ofthe size of the vehicle. Such a process of developing parts is rathercostly. In view of the current circumstances where cost reduction is animposing requirement to be met regardless of large machines and smallmachines, efforts are being paid to develop parts that can be commonlyused for machines of any sizes for the purpose of cost reduction.

[0007] Additionally, from the operator's viewpoint seeking forcomfortable operations, it is necessary that sufficient space isprovided around the operator seat. Therefore, there is a tendency ofmounting a cab developed for a large hydraulic excavator on a small onein an effort of providing parts that are commonly used to all the types.However, when a cab developed for a large hydraulic excavator is appliedto the upper swing body of a small hydraulic excavator, it goes out ofthe upper swing body to a large extent.

SUMMARY OF THE INVENTION

[0008] A principal object of the present invention is to provide aservice vehicle of the type in which the upper swing body can turnwithin the width of the vehicle (to be referred to as intra-width sluingtype hereafter) and for which large parts including a canopy or a cabcan be commonly used with large service vehicles so as to significantlyreduce the cost.

[0009] A service vehicle according to the present invention comprises anupper swing body mounted on the vehicle main body and adapted to turnwithin the width of the vehicle main body and provided with a scheme fordownsizing a lateral section of the seat (to be referred to as seatlateral section hereafter) on the upper swing body.

[0010] Any appropriate downsizing scheme may be used for the purpose ofthe invention. For example, it may be realized by using a flexible airchamber that is separated from a main tank of the hydraulic tank inorder to reduce the overall dimensions of the hydraulic tank and hencethose of a seat lateral section. Alternatively, it may be realized byusing a bubble removing device for removing bubbles from hydraulic fluidin order to reduce the overall dimensions of the hydraulic tank andhence those of a seat lateral section. Still alternatively, it may berealized by part or all of the hydraulic tank disposed in a seat lateralsection in an ingenious way of improving the efficiency of arrangementin the seat lateral section so as to downsize the lateral section.

[0011] Thus, when a service vehicle of the intra-width sluing type isprovided with such a downsizing scheme, the seat lateral section isultimately downsized so that space is generously provided around theseat. Therefore, unlike the past experiences, a canopy or a cab adaptedto a large service vehicle can be reliably and securely arranged on theupper swing body of a small service vehicle. Then, such a large part canbe commonly used for both large and small service vehicles toconsequently reduce the cost of manufacturing a service vehicle.

[0012] Preferably, in a service vehicle according to the invention, astep section is provided in front of the seat lateral section on theupper swing body so as to allow the operator to move from the seat tothe outside of the vehicle and vice versa.

[0013] In the case of a hydraulic excavator not provided with a cab(e.g., of the canopy model), the seat is open to the outside at everyside thereof unlike the cab model so that the operator can easily getonto and away from the seat. However, a large lateral section isarranged at a lateral side (normally right side) of the seat of theupper swing body of the conventional canopy model to contain a hydraulictank, a control valve or the like there and therefore the operator isforced to get onto and away from the seat from the side opposite to thelateral section as in the case of the cab model. Additionally, since theseat is open at the front side thereof, the operator may get into andaway from the seat through the front side. However, actually it is noteasy for the operator to do so because the lateral section provides aconsiderable obstacle for the moving operator. In short, it is difficultto satisfactorily exploit the advantages of conventional servicevehicles of the canopy model and there is a demand for improved servicevehicles that allows the operator to easily get onto and away from theseat of the vehicle.

[0014] According to the invention, a downsizing scheme is provided todownsize the seat lateral section and squeeze out a space and a stepsection is provided at the front side of the seat lateral section toutilize the space produced by the downsizing scheme. Thus, the operatorcan get onto the seat from the outside by way of the seat lateralsection, using the step section. The operator can also get away from theseat to the outside in a similar manner to fully exploit the advantagesof the canopy model.

[0015] Preferably, a service vehicle comprising an upper swing bodymounted on the vehicle main body and adapted to turn within the width ofthe vehicle according to the invention is provided with a hydraulicallydriven work implement arranged substantially at the center of the upperswing body, a cab for covering the seat mounted on the upper swing bodyand a downsizing scheme for downsizing the seat lateral section on theupper swing body, the work implement being apt to tilt toward the seatside across a fitting section of the upper swing body.

[0016] Since the cab of a hydraulic excavator is normally box-shaped andlarger than a canopy, the front side of the cab is located forward onthe vehicle main body relative to the front side of the canopy of asimilar hydraulic excavator. In other words, the cab is located close tothe work implement. Therefore, in a conventional hydraulic excavator ofthe cab model, the boom of the work implement cannot be tilted towardthe seat side across the fitting section thereof. Thus, it is notpossible for a hydraulic excavator of the cab model to show a maximumdumping height and a maximum digging height that are as high as those ofa hydraulic excavator of the canopy model.

[0017] To the contrary, in a hydraulic excavator of the cab modelaccording to the invention, the cab can be arranged at a positiondisplaced rearward if compared with that of a conventional hydraulicexcavator because the seat lateral section is downsized by thedownsizing scheme so that the work implement can be tilted toward theseat side across the fitting section thereof to a large extent. Thus,the operating range of the work implement of a hydraulic excavator ofthe cab model is made as large as that of the work implement of acomparable hydraulic excavator of the canopy model. Obviously, such acab model service vehicle can be handled with ease.

[0018] Preferably, a service vehicle comprising an upper swing bodymounted on the vehicle main body and adapted to turn within the width ofthe vehicle according to the invention is provided with a hydraulicallydriven work implement and a downsizing scheme for downsizing the seatlateral section on the upper swing body, the service vehicle beingeither of the model having a cab covering the seat arranged on the upperswing body or of the model not having a cab, the work implement beingcommon to the two models.

[0019] As described above with regard to a service vehicle according tothe invention, the operating range of the work implement of aconventional service vehicle of the cab model and that of the workimplement of a conventional service vehicle of the canopy model differfrom each other. In other words, the manufacturing specifications of theformer work implement differ from those of the latter work implement.More specifically, a special mechanism for limiting the movement of theboom may be provided in a hydraulic excavator of the cab model having asmall operating range to increase the number of components. Then, theoperation of servicing work implements that are manufactured accordingto different manufacturing specifications will be a cumbersome one.

[0020] To the contrary, according to the invention, the cab of a cabmodel service vehicle can be displaced to allow the use of a workimplement having an operating range as large as that of the workimplement of a canopy model service vehicle so that work implements canbe commonly used for service vehicles regardless of the model of thevehicle. In other words, no specially designed mechanism is needed forservice vehicles of the cab model and work implements can be controlledwith ease before they are mounted on service vehicles. Then, costreduction will be promoted for such service vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a schematic lateral view of the first embodiment ofservice vehicle, showing the entire profile of the canopy model;

[0022]FIG. 2 is a schematic plan view of the first embodiment, showingthe entire profile thereof;

[0023]FIG. 3 is a schematic cross sectional view of the main tank of thehydraulic tank of the first embodiment;

[0024]FIG. 4 is a schematic perspective view of the variable capacitytank of the hydraulic tank of the first embodiment, illustrating how itis fitted in position;

[0025]FIG. 5 is a schematic perspective view of the variable capacitytank of the first embodiment, illustrating the entire profile thereof;

[0026]FIG. 6 is a schematic cross sectional view of the variablecapacity tank of the first embodiment;

[0027]FIG. 7 is a schematic illustration of the difference between thehydraulic tank of the first embodiment and that of a conventionalservice vehicle;

[0028]FIG. 8 is a schematic lateral view of the second embodiment ofservice vehicle, showing the entire profile of the cab model;

[0029]FIG. 9 is a schematic plan view of the second embodiment, showingthe entire profile thereof;

[0030]FIG. 10 is a schematic perspective view of the first modifiedembodiment of the invention;

[0031]FIG. 11 is a schematic perspective view of the second modifiedembodiment of the invention;

[0032]FIG. 12 is a schematic perspective view of the third modifiedembodiment of the invention;

[0033]FIG. 13 is a schematic perspective view of the fourth modifiedembodiment of the invention; and

[0034]FIG. 14 is a schematic perspective view of the fifth modifiedembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Now, the present invention will be described by referring to theaccompanying drawings that illustrate preferred embodiments of theinvention.

[0036] Of the embodiments that will be described hereafter, the firstone is a hydraulic excavator (service vehicle) 1 without a cab and thesecond one is a hydraulic excavator (service vehicle) 2 of the cabmodel.

[0037] A hydraulic excavator 1 without a cab may be that of the canopymodel or of the model that does not even have a canopy. In short, it isa hydraulic excavator of any model that does not have a cab. Thecomponents that are common to both the hydraulic excavator 1 of thefirst embodiment and the hydraulic excavator 2 of the second embodimentwill be described only by referring to the hydraulic excavator 1 of thecanopy model of the first embodiment and, unless necessary, will not bedescribed any further in terms of the hydraulic excavator 2 of the cabmodel of the second embodiment.

1st Embodiment Canopy Model

[0038]FIG. 1 is a schematic lateral view showing the entire profile ofthe hydraulic excavator 1 of the canopy model and FIG. 2 is a schematicplan view showing the entire profile thereof. Not that a work implement40, which will be described hereafter, is tilted differently in FIGS. 1and 2.

[0039] The hydraulic excavator 1 comprises a vehicle main body 10including a pair of lower running bodies 11 of the crawler type, anupper swing body 20 arranged on the vehicle main body 10 so as to beable to swing, a seat 30 arranged at an upper area of the upper swingbody 20 and a work implement 40 arranged at the front side (in a statewhere the operator is properly sitting on the seat 30 and at the leftside in FIG. 1) of the upper swing body 20. A cover type canopy 31 isarranged above the seat 30.

[0040] As seen from FIG. 2, the hydraulic excavator 1 is of theintra-width sluing type. In other words, the upper swing body 20 canswing within the width W of the vehicle main body 10. A fitting section21 that projects forward is arranged at the front side of the upperswing body 20 at a position substantially at the middle in the lateraldirection of the vehicle main body 10. The work implement 40 is securedto the fitting section 21.

[0041] In the hydraulic excavator 1, the lower running bodies 11 and theblade 12 that are arranged at the vehicle main body 10 and the workimplement 40 are hydraulically driven in a conventional manner. Ahydraulic pump (not shown) for generating hydraulic pressure, an engineand other components (not shown) for driving the hydraulic pump aremounted in an engine room 13 that is arranged at the rear side of thevehicle main body 10.

[0042] A seat lateral section 14 that stands substantially as high asthe engine room 13 is arranged to the right side of the seat 30 on thevehicle main body 10. The seat lateral section 14 contains therein acontrol valve (not shown) for controlling the hydraulic pressure fromthe hydraulic pump, a fuel tank (not shown) and a hydraulic tank 50shown in FIGS. 3 through 5.

[0043] The work implement 40 that is driven by the hydraulic pressureapplied from the hydraulic tank 50 is structurally a conventional one.More specifically, it has a boom 41 pivoted to the fitting section 21 ofthe upper swing body 20, an arm 42 pivoted to the front end of the boom41 and a bucket 43 pivoted to the front end of the arm 42, which areadapted to be driven to turn respectively by means of a boom cylinder44, an arm cylinder 45 and a bucket cylinder 46. The boom 41 can betilted toward the seat 30 across the fitting section 21 (FIG. 1).

[0044] The work implement 40 is operated by means of work implementlevers 32 arranged at the lateral sides of the seat 30, while the lowerrunning bodies 11 are operated by means of running levers 33 and runningpedals 34 arranged in front of the seat 30. The seat 30 on which theoperator sits is placed rearward at a position close to the center onthe upper swing body 20 if compared with that of a comparableconventional service vehicle. Therefore, a through area 37 is providedon and above a floor 36 behind a handrail 35.

[0045] The seat lateral section 14 located adjacent to the seat 30 isdownsized if compared with that of a conventional service vehicle asindicated by a dotted broken line in FIG. 2 to provide space forarranging a step section 38 that continues from the through area 37 andis located in front of the seat lateral section 14. While the operatoris forced to move through a narrow gap between the fitting section 21and the seat lateral section 14 (along the dotted broken lines witharrows) on a conventional service vehicle, space is generously providedin front of the seat lateral section 14 due to the provision of the stepsection 38 so that the operator can move freely from the seat 30 to theoutside and also the other way (along the solid lines with arrows).

[0046] Now, the hydraulic tank 50 will be described by referring toFIGS. 3 through 5.

[0047] The hydraulic tank 50 is of the separable type that includes amain tank 51 as shown in FIG. 3 and a variable capacity tank 52 as shownin FIGS. 4 and 5. The main tank 51 mainly contains hydraulic fluid Ftherein, whereas air flows into and out of the variable capacity tank52.

[0048] The main tank 51 is a rigid tank typically made of metal andprovided at the bottom thereof with an oil outlet port 511 through whichhydraulic fluid is driven out toward the cylinders 44 through 46 bymeans of a hydraulic pump (not shown). A suction strainer 512 isarranged so as to cover the oil outlet port 511. An oil return port 513is arranged at the top of the main tank 51 so that hydraulic fluid isbrought back to the main tank 51 from the cylinders 44 through 46 by wayof the oil return port 513. The hydraulic fluid that is returned by wayof the oil return port 513 is received in the main tank 51 by way of afilter 53 and a bubble removing device 60.

[0049] The bubble removing device 60 is of the cyclone type. Ashydraulic fluid containing bubbles and coming from the filter 53 is madeto flow into a cyclone chamber 61 along a tangential direction, aswirling flow of hydraulic fluid is produced in the cyclone chamber 61.As a swirling flow arises, bubbles having a small specific gravity areforced to come to the center and concentrate there. Concentrated bubblesare then forced to move through the flow path 62 for delivering bubblesand driven into the hydraulic fluid contained in the main tank 51through a delivery port 63 then they move upward and become dischargedinto the air. The hydraulic fluid from which bubbles are removed is thenmade to gush into the hydraulic fluid already found in the main tank 51through a lower part of the cyclone chamber 61.

[0050] Conventional hydraulic tanks are not provided with such a bubbleremoving device 60 and therefore the hydraulic fluid returning to thehydraulic tank contains bubbles to a large extent. Conventionalhydraulic tanks are designed to contain a large volume of hydraulicfluid and the hydraulic fluid that is returned to the tank is preventedfrom being driven out immediately for the purpose of removing bubbles.In other words, time is given to the hydraulic fluid that is returned tothe tank so that bubbles may move up and become discharged into the aircontained in the air chamber 514 during the time. Such a conventionalhydraulic tank is by far larger than the hydraulic tank 50 of thisembodiment.

[0051] Differently stated, the volume of hydraulic fluid in thehydraulic tank 50 (particularly in the main tank 51) can be reduced toby turn reduce the capacity of the hydraulic tank 50 by providing abubble removing device 60 so that the hydraulic tank 50 and hence theseat lateral section 14 where the hydraulic tank 50 is arranged can bedownsized. Thus, the bubble removing device 60 of this embodimentoperates as downsizing scheme for the purpose of the present invention.The bubble removing device 60 is not limited to the cyclone type and mayalternatively be of any other type. Additionally, it may be arrangedoutside the main tank 51.

[0052] Meanwhile, referring to FIG. 2, the level A of the surface ofhydraulic fluid in the main tank 51 corresponds to certain intermediarypositions of the cylinders 44 through 46. The level L of the surface ofhydraulic fluid is the minimum (lowest) level and corresponds to thehead side positions of the pistons of the cylinders 44 through 46, wherea large volume of hydraulic fluid is sent to the bottom sides of thecylinders from the main tank 51. Finally, the level H of the surface ofhydraulic fluid is the maximum (highest) level and corresponds to thebottom side positions of the pistons of the cylinders, where a largevolume of hydraulic fluid is returned from the bottom sides of thecylinders to the main tank 51.

[0053] The capacity of the main tank 51 is substantially equal to thelargest volume of hydraulic fluid in the hydraulic tank 50 when thesurface of hydraulic fluid is at level H. When the surface of hydraulicfluid is at level H, the air chamber 514 does not practically exist atall in the main tank 51. This is because, as the surface of hydraulicfluid in the main tank 51 rises from level L or level A to level H, theair contained in the air chamber 514 is forced to move into the variablecapacity tank 52 through a communicating section 515.

[0054] The variable capacity tank 52 is formed to a flexible, hollow andhighly airtight mattress-shape typically by using a multilayer sheet ofsynthetic resin such as polychloroprene or polyamide. In thisembodiment, it is arranged at the rear surface side of the upper cover15 that the seat lateral section 14 comprises. Thus, one of the surfacesof the variable capacity tank 52 is made to operate as fitting surfacesection 521 to be fitted to the upper cover 15 by an appropriate fittingunit and the opposite surface is made to operate as movable surfacesection 522. The surface sections 521, 522 are linked together by meansof a large number of fiber-like confining members 523 that are typicallymade of polyester. A communicating section 524 is arranged at a part ofthe movable surface section 522.

[0055] The communicating section 524 is held in communication with thecommunicating section 515 of the main tank 51 by way of a tube (see FIG.7) or the like so that air may flow into and from the air chamber 514 ofthe main tank 51 by way of the communicating section 524. As air movesfrom the air chamber 514 into the variable capacity tank 52, the tank 52inflates. Since the movable surface section 522 is confined for theextent of its movement and hence for the extent of inflation of thevariable capacity tank 52 by the confining members 523, themattress-shape of the variable capacity tank 52 is maintained if thetank 52 is inflated. In other words, any central part of the variablecapacity tank 52 does not project disproportionately and the entirevariable capacity tank 52 maintains a uniform thickness. Furthermore,the variable capacity tank 52 is fitted in the opening section 16A ofthe sound absorbing member 16 bonded to the upper cover 15 so as to beburied there and hence, when it is inflated maximally (as the surface ofhydraulic fluid in the main tank 51 is at level H), the movable surfacesection 522 comes to be substantially flush against the surface of thesound absorbing member 16.

[0056] The maximum capacity of the variable capacity tank 52 is smallerthan the capacity of the air chamber 514 defined by the minimum level Lof the surface of hydraulic fluid in the main tank 51. As a matter offact, it is about a half of the capacity of the air chamber 514 in thisembodiment. In other words, as the surface of hydraulic fluid in themain tank 51 rises from level L to level H, the capacity of the airchamber 514 falls from the largest to nil to maximize the volume of airthat is forced to move from the main tank 51 into the variable capacitytank 52. The air that is forced to move into the variable capacity tank52 is compressed and stored in the latter. Thus, the air pressure in thevariable capacity tank 52 is nearly doubled from the air pressure in theair chamber 514 and the variable capacity tank 52 is formed to bear thispressure. Therefore, the hydraulic tank 50 as a whole can be downsizedif compared with the metal-made hydraulic tank of a conventional servicevehicle. This will be discussed below in greater detail by referring toFIG. 7 that illustrates a hydraulic tank of the prior art.

[0057] The metal-made hydraulic tank 90 of the prior art illustrated inFIG. 7 is provided with an air chamber 91 that corresponds to the airchamber 514 of this embodiment in order to accommodate changes in thevolume of hydraulic fluid stored in the tank 90. The hydraulic tank 90is additionally provided with another air chamber 92 having a capacitysubstantially equal to that of the air chamber 91 to make the entirehydraulic tank 90 very large. Such a large tank 90 is needed in order tosuppress the air pressure exerted on the surface of hydraulic fluid atthe maximum level H to about twice (2 P) of the air pressure (1 P)exerted on the surface of hydraulic fluid at the minimum level L.

[0058] To the contrary, the space that corresponds to the air chamber 92of the prior art is eliminated from the main tank 51 of this embodiment.In other words, the main tank 51 is provided only with an air chamber514 that corresponds to the air chamber 91 of the prior art.Additionally, the variable capacity tank 52 is arranged separately fromthe main tank 51 so that air can be moved away from the air chamber 514(that corresponds to the air chamber 91 of the prior art). The maximumcapacity of the variable capacity tank 52 is made to be equal to a halfof the capacity of the air chamber 514 in order to make the air pressureexerted on the surface of hydraulic fluid to be equal to 2 P as in thecase of the prior art when the air in the air chamber 514 is forced out.

[0059] Thus, the hydraulic tank 50 of this embodiment includes only themain tank 51 that can contain hydraulic fluid up to level H and thevariable capacity tank 52 having a capacity that is equal to a half ofthe capacity of the air chamber 91 (which is equal to the capacity ofthe air chamber 92) of the prior art. Therefore, the hydraulic tank 50of this embodiment is downsized if compared with the hydraulic tank 90of the prior art due to the arrangement of separating the main tank 51and the variable capacity tank 52 of the hydraulic tank 50. As a result,the seat lateral section 14 for containing the hydraulic tank 50 of thisembodiment is downsized. Thus, the arrangement of separating the maintank 51 and the variable capacity tank 52 of the hydraulic tank 50 alsooperates as downsizing scheme for the purpose of the invention. Further,in this embodiment, as described before, bubble removing device 60 inthe main tank 51 of the hydraulic tank 90 also operates as downsizingscheme. Note that the bubble removing device 60 in the main tank 51 isnot shown in FIG. 7.

[0060] Furthermore, in this embodiment, the variable capacity tank 52 isfitted to the part of the rear surface of the upper cover 15 where thesound absorbing member 16 may need to be bonded if the arrangement ofthe prior art is preserved. In other words, the variable capacity tank52 does not require space dedicated to it. Thus, the arrangement offitting the variable capacity tank 52 to the rear surface of the uppercover 15 also operates as downsizing scheme for the purpose of thepresent invention because it reduces the necessary internal space of theseat lateral section 14 and hence downsizes the latter.

[0061] Because of the above described downsizing scheme, the seatlateral section 14 is downsized to provide space on the upper swing body20 so that consequently the seat 30 is placed rearward at a positionclose to the center on the upper swing body 20 if compared with that ofa comparable conventional service vehicle. Therefore, a through area 37and a step section 38 can be provided on and above the floor 36.Additionally, a canopy 31 that is larger than its counterpart of theprior art can be arranged to cover the seat 30 due to the newly providedspace. In other words, a canopy 31 that is used in a canopy modelhydraulic excavator of a larger type can be applied to the embodiment.

2nd Embodiment Cab Model

[0062] A hydraulic excavator 2 of the cab model will be described byreferring to FIGS. 8 and 9.

[0063]FIG. 8 is a schematic lateral view of the hydraulic excavator 2,showing the entire profile of the cab model and FIG. 9 is a schematicplan view of the second embodiment, showing the entire profile thereof.Note that the work implement 40 is tilted differently in FIGS. 8 and 9.

[0064] The hydraulic excavator 2 of this embodiment differs from thehydraulic excavator 1 of the first embodiment in that the canopy 31 ofthe hydraulic excavator 1 is replaced with a box-shaped cab 39.Otherwise, the hydraulic excavator 2 has a configuration basically sameas that of the hydraulic excavator 1. In other words, the manufacturingspecifications of the work implement 40 are common to this hydraulicexcavator 2 and the hydraulic excavator 1. Therefore, the boom 41 can betilted toward the seat (not shown) across the fitting section 21

[0065] The arrangement of providing a bubble removing device 60, that ofseparating the main tank 51 and the variable capacity tank 52 of thehydraulic tank 50 and that of fitting the variable capacity tank 52 tothe rear surface of the upper cover 15 are also applied to the hydraulicexcavator 2 of this embodiment as downsizing scheme for the purpose ofthe invention. Thus, with these arrangements, the seat lateral section14 is downsized to provide space on the upper swing body 20 so thatconsequently the seat 30 (FIG. 1) and the cab 39 are placed rearward ata position close to the center on the upper swing body 20 if comparedwith that of a comparable conventional cab model.

[0066] Additionally, the cab 39 is made to have a larger capacity ifcompared with a comparable cab model of the prior art due to the spaceproduced as a result of downsizing the seat lateral section 14. In otherwords, a cab 39 that is used in a cab model hydraulic excavator of alarger type can be applied to the embodiment. Note that, while the frontsurface of the cab 39 is advanced so as to be flush against the surfaceof the upper swing body 20 in the cab model of this embodiment, it maybe retracted so as to secure the through area 37. If the through area 37is secured, the capacity of the cab 39 is not reduced significantly. Inother words, it is sufficiently large if compared with that of the cabof a conventional service vehicle of the cab model.

[0067] The above described first and second embodiments provide thefollowing advantages.

[0068] (1) The seat lateral section 14 of the hydraulic excavator 1 andthat of the hydraulic excavator 2 can be downsized by adoptingdownsizing scheme including the arrangement of providing a bubbleremoving device 60 for removing bubbles from hydraulic fluid, that ofusing a hydraulic tank 50 having a main tank 51 and a variable capacitytank 52 that are separated from each other and that of fitting thevariable capacity tank 52 to the rear surface of the upper cover 15. Asa result, a large space can be provided around the seat 30. Thus, acanopy 31 or a cab 39 adapted to a large hydraulic excavator can besecurely arranged on the upper swing body 20 of a small hydraulicexcavator 1 or 2, whichever appropriate. Since such large parts can becommonly used for both large hydraulic excavators and small hydraulicexcavators, it is now possible to remarkably reduce the manufacturingcost of a service vehicle.

[0069] (2) Due to the provision of downsizing scheme, the seat lateralsection 14 of the hydraulic excavator 1 or 2 is downsized to allow astep section 38 to be arranged in front of the seat lateral section 14.Thus, a large space can be provided near the seat lateral section 14 toallow the operator to move through it with ease. Therefore, particularlyin the case of a hydraulic excavator of the canopy model, the operatorcan get easily onto the seat 30 from the outside and move away easilyfrom the seat 30 to the outside by way of the step section 38 locatednear the seat lateral section 14. Therefore, the advantages of thecanopy model can be effectively exploited.

[0070] (3) Since the seat 30 is placed rearward at a position close tothe center on the upper swing body 20 if compared with that of acomparable conventional service vehicle, a through area 37 can beprovided behind the handrail 35 in the hydraulic excavator I of thecanopy model. The through area 37 may be made to communicate with thestep section 38. Then, the operator can move through the hydraulicexcavator 1 by way of the through area 37 and the step section 38without detouring around the vehicle if the boom 41 or the like istilted forward and held immobile and hence nothing blocks the operatortrying to move through the through area 37 and the step section 38.

[0071] (4) The cab 39 mounted on the hydraulic excavator 2 is displacedrearward as a result of the provision of downsizing scheme so that theboom 41 of the work implement 40 can be tilted toward the seat 30 (thecab 39) across the fitting section 21 to a large extent and hence thefront end of the boom 41 and that of the arm 42 of the work implement 40can be held high like those of the hydraulic excavator 1 of the canopymodel. Thus, a larger maximum dumping height and a larger maximumdigging height can be secured for the hydraulic excavator 2. Namely, thehydraulic excavator 2 of the cab model can be made to have a workablerange that is as large as the hydraulic excavator 1 of the canopy model.Then, the hydraulic excavator 2 of the cab model can be handled withease.

[0072] (5) A work implement 40 can be commonly used for the hydraulicexcavator 1 and the hydraulic excavator 2. In other words, the structureof the work implement 40 does not need to be modified depending on themodel with which it is used and the work implement 40 can be handled andcontrolled with ease before it is mounted on the upper swing body 20 tofurther reduce the cost.

[0073] (6) The canopy 31 of the hydraulic excavator 1 and the cab 39 ofthe hydraulic excavator 2 are those that are compatible with largerhydraulic excavators. Thus, the canopy 31 is more effective for blockingsunbeams and raindrops than that of a smaller hydraulic excavator,whereas the cab 39 provides a large internal space to allow the operatorto operate more comfortably.

[0074] (7) Since a bubble removing device 60 is used as downsizingscheme, it is no longer necessary to install a large capacity hydraulictank of the prior art. Thus, particularly the main tank 51 of thehydraulic tank 50 can be made sufficiently small to reliably downsizethe seat lateral section 14.

[0075] (8) Since the hydraulic tank 50 is made to include a main tank 51and a variable capacity tank 52 that are separated from each other forthe purpose of downsizing, the maximum capacity of the variable capacitytank 52 for forming an air chamber 514 can be sufficiently reduced to byturn reduce the overall dimensions of the hydraulic tank 50. Thus, theseat lateral section 14 can be reliably downsized.

[0076] (9) Since the variable capacity tank 52 is arranged at the rearsurface of the upper cover 15 also for the purpose of downsizing, thespace where the sound absorbing member 16 is bonded for the prior artcan be effectively utilized in a service vehicle according to theinvention. Thus, it is no longer necessary to provide a space dedicatedto the variable capacity tank 52 in the seat lateral section 14 so thatthe latter can be further downsized.

Modified Embodiments

[0077] The present invention is by no means limited to the abovedescribed embodiments, which may be modified particularly in terms ofconfiguration so as to achieve the object of the invention as will bedescribed below.

[0078] For example, the variable capacity tank 52 of each of the abovedescribed embodiments is realized by linking the fitting surface section521 and the movable surface section 522 together by means of fiber-likeconfining members 523 so that the variable capacity tank 52 may inflate,keeping its mattress-shape and the relative positions of the surfacesections 521, 522. However, the structure of the variable capacity tank52 is not limited thereto. Any of the structures illustrated in FIGS. 10through 13 may alternatively be used.

[0079]FIG. 10 (the first modified embodiment) shows a variable capacitytank 52 realized by linking the fitting surface section 521 and themovable surface section 522 together by means of a plurality of flatpartition wall sections 525 arranged at regular intervals in a givendirection. Each of the partition wall sections 525 is provided withaperture holes 525A having an appropriate profile so that the internalspaces that are separated by the partition wall sections 525 communicatewith each other.

[0080]FIG. 11 (the second modified embodiment) shows a variable capacitytank 52 realized by arranging the fitting surface section 521 and themovable surface section 522 close to each other and linking themtogether by means of binding members 526 from the opposite externalsides. Alternatively, the fitting surface section 521 and the movablesurface section 522 may be linked together by spot bonding, typicallyusing the technique of thermal fusion bonding without using bindingmembers 526.

[0081]FIG. 12 (the third modified embodiment) shows a variable capacitytank 52 realized by directly bonding the fitting surface section 521 andthe movable surface section 522 together in a given direction at regularintervals typically by using the technique of thermal fusion bonding.Note that the two surface sections 521, 522 are not bonded over theentire width thereof and have a lower unbonded zone that allows all thepartitioned internal spaces to communicate with each other.

[0082]FIG. 13 (the fourth modified embodiment) shows a variable capacitytank 52 realized by directly bonding the fitting surface section 521 andthe movable surface section 522 together in a given direction at regularintervals typically by using the technique of thermal fusion bondingover the entire width thereof. The variable capacity tank 52 is providedwith a branching member 527 branched from a communicating section 524 inorder to allow all the partitioned internal spaces to communicate witheach other.

[0083] In short, the structure of the variable capacity tank 52 may bedefined appropriately, taking the position where it is arranged, itsexternal profile and its material into consideration. In other words, astructure other than those illustrated in FIGS. 10 through 13 mayalternatively be used for the purpose of the invention.

[0084] As for the hydraulic tank 50 of each of the above describedembodiments, the main tank 51 is arranged in the seat lateral section 14like that of the prior art while the variable capacity tank 51 isarranged at the rear surface of the upper cover 15. However, thehydraulic tank 50 may be arranged at the rear surface of the upper cover15 regardless if the tanks 51, 52 are put together or arrangedseparately. For example, FIG. 14 (the fifth modified embodiment) shows ahydraulic tank 50 fitted to the rear surface of the upper cover 15 andformed by integrally combining the tanks 51, 52.

[0085] The hydraulic tank 50 is made to show an external profile thatfits the upper cover 15 or the sound absorbing member that is otherwiseto be bonded there. All the spaces to be used for bonding the soundabsorbing member is utilized for the purpose of fitting the hydraulictank 50 there. With this arrangement, no problem arises in terms of thesound insulation effect because the hydraulic tank 50 provides a soundabsorbing effect. The arrangement of fitting the hydraulic tank 50 tothe upper cover 15 in place of a sound absorbing member constitutesanother downsizing scheme for the purpose of the present inventionbecause no dedicated space needs to be provided to contain the hydraulictank 50 in the seat lateral section 14 and hence the seat lateralsection 14 is downsized.

[0086] Further, arrangement of making the whole hydraulic tank 50flexible also constitutes a downsizing scheme for the purpose of thepresent invention. In this case, the hydraulic tank 50 can be providedat the space that corresponds to the heretofore dead space in the seatlateral section 14. Thus, it is no longer necessary to provide a spacededicated to the hydraulic tank 50 in the seat lateral section 14 sothat the latter can be further downsized.

[0087] While the arrangement of separating the rigid main tank 51 andthe flexible variable capacity tank 52 of the hydraulic tank 50constitutes a downsizing scheme for the purpose of the presentinvention, both the main tank 51 and the variable capacity tank 52 maybe made rigid or flexible so long as they are separated from each otherbecause separation of the main tank 51 and the variable capacity tank 52means that they are arranged in a distributed manner to fully exploitthe dead space in the seat lateral section 14.

[0088] Additionally, when the rigid part and the flexible part of thehydraulic tank 50 are put together, such an arrangement can alsoconstitute a downsizing scheme for the purpose of the invention becausethe hydraulic tank 50 can be downsized and hence the seat lateralsection 14 can also be downsized as illustrated in FIG. 7.

[0089] For the purpose of the invention, any other downsizing scheme canalso be provided when the positional arrangement and the structure ofthe hydraulic tank 50 are devised in a unique way. Furthermore, otherdownsizing scheme can additionally be provided when the positionalarrangement and the structure of any of the hydraulic control valve andthe engine are devised so as to downsize the seat lateral section 14.

[0090] A service vehicle according to the invention is not limited to ahydraulic excavator as described above in terms of embodiments. A numberand arrangement of hydraulic pump, hydraulic cylinder, an engine andother components of a hydraulic excavator can be changed. It mayalternatively a bulldozer or some other construction machine or civilengineering machine.

What is claimed is:
 1. A service vehicle comprising: an upper swing bodymounted on a vehicle main body and adapted to turn within the width ofthe vehicle main body: and a downsizing scheme for downsizing a lateralsection of the seat on the upper swing body.
 2. The service vehicleaccording to claim 1, wherein a step section is provided in front of theseat lateral section on the upper swing body so as to allow an operatorto move from a seat to the outside of the vehicle and vice versa.
 3. Theservice vehicle according to claim 1, further comprising: ahydraulically driven work implement arranged substantially at the centerof the upper swing body; a cab for covering the seat mounted on theupper swing body; and a downsizing scheme for downsizing the seatlateral section on the upper swing body: the work implement being apt totilt toward the seat across the fitting section of the upper swing body.4. The service vehicle according to claim 2, further comprising: ahydraulically driven work implement arranged substantially at the centerof the upper swing body; a cab for covering the seat mounted on theupper swing body; and a downsizing scheme for downsizing the seatlateral section on the upper swing body: the work implement being apt totilt toward the seat across the fitting section of the upper swing body.5. The service vehicle according to claim 1, further comprising: ahydraulically driven work implement: and a downsizing scheme fordownsizing the seat lateral section on the upper swing body: the servicevehicle being either of the model having a cab covering the seatarranged on the upper swing body or of the model not having a cab; thework implement being common to the two models.
 6. The service vehicleaccording to claim 2, further comprising: a hydraulically driven workimplement: and a downsizing scheme for downsizing the seat lateralsection on the upper swing body: the service vehicle being either of themodel having a cab covering the seat arranged on the upper swing body orof the model not having a cab; the work implement being common to thetwo models.
 7. The service vehicle according to claim 3, furthercomprising: a hydraulically driven work implement: and a downsizingscheme for downsizing the seat lateral section on the upper swing body:the service vehicle being either of the model having a cab covering theseat arranged on the upper swing body or of the model not having a cab;the work implement being common to the two models.
 8. The servicevehicle according to claim 4, further comprising: a hydraulically drivenwork implement: and a downsizing scheme for downsizing the seat lateralsection on the upper swing body: the service vehicle being either of themodel having a cab covering the seat arranged on the upper swing body orof the model not having a cab; the work implement being common to thetwo models.